Several nutrient-signaling pathways that extend life span have been described in model organisms. Thus, parallel and redundant signaling pathways that are similar across species might be subject to experimental manipulation. Here, we develop a PCR-based technique for testing the hypothesis that mitotic accumulation of extra-chromosomal ribosomal DNA circles might also determine life span in human cells. Using resveratrol, a phytochemical that counters age-related signs, we find treatment-dependent subcellular accumulations of extra-chromosomal 5S ribosomal DNA in human cell lines. These data suggest an association between DNA circles and intrinsic aging and demonstrate the utility of a PCRbased technique for studying the accumulation of dysfunctional molecules that promote senescence.